Game practice apparatus



March 5, 1957 Filed Dec. 13, 1954 L. G. SIMJIAN GAME PRACTICE APPARATUS 5 Sheets-Sheet l LUTHER G. SIMJIAN INVENTOR ATTORNEY March 5, 1957 L. G. SIMJIAN 2,784,001

GAME PRACTICE APPARATUS Filed Dec. 13, 1954 FIG.4

5 Sheets-Sheet 2 LUTHER G. SIMJIAN INVENTOR ATTORNEY March 5, 1957 SIMJIAN 2,784,001

GAME: PRACTICE APPARATUS Filed Dec. 13, 1954 FIG.8

5 Sheets-Sheet 3 LUTHER G. SIMJIAN INVENTOR I BY ATTORNEY March 5, 1957 L. s. SIMJIAN GAME PRACTICE APPARATUS 5 Sheets-Sheet 4 Filed Dec. 13, 1954 LUTHER s smmu INVENTOR ATTORNEY IIIIMIIM IJ March 5, 1957 L. s. SIMJIAN 2,734,001

GAME PRACTICE APPARATUS Filed Dec. 15, 1954 s Sheets-Sheet 5 n 5 Q\ Q? nun l I I nun'u z 7 I w v I 8 Fa 5 I I l [1' I x i i i LUTHER G. SIMJIAN INVENTOR ATTORNEY United States atent O 2,7845001 GAME PRACTICE APPARATUS Luther G. Simjian, Greenwich, Conn., assignor to The Reflectone Corporation, Stamford, Conn a corporation of Connecticut Application December 13, 1954, Serial No. 474,812 6 Claims. (Cl. 273185) This application is a continuation-in-part of my cpending application, Serial No. 377,202, filed August 28, 1953, for a computing system which has now been abandoned.

This invention relates to a computing system for determining the flight of a struck missile and to determine its means for determining the direction and velocity of the missile.

Several devices have been used to measure the approximate velocity of a free ball which has been struck with a club or bat. Some of these devices have been used for developing driving proficiency by employing a golf ball and using golf clubs. However, these prior art devices were capable of measuring only the total force given to the ball and they did not determine the direction of the ball, its probable final position, and the spin imparted to the ball.

One of the objects of this invention is to provide an improved computing system for struck missiles which s one or more of the disadvantages and limitations of prior art arrangements.

Another object of the invention is to determine the Another object of the invention is the determination of a missile trajectory using free missiles not held captive by force-measuring coupling arrangements.

One feature of the invention comprises a computing system for determining the path of a struck missile and includes three arrays of contact means for determining the position of impact within a restricted range. A timing device measures the time interval between the start time and the arrival of the missile at the first target. The invention also includes a means for determining the spin given to a struck missile by the position of impact on a second target.

Another feature of the invention includes a display device for showing the flight of a struck missile on a large screen. An additional feature shows the trajectory of a struck missile on a screen giving the illusion of three dimensions utilizing two crossed polarized light beams.

Another feature of the invention includes a computing device of the analogue type which receives the data provided by the targets and timing device and produces data which controls a display device to show the flight of a free missile having the same impelling force.

For a better understanding of the present invention together with other and further objects thereof, reference is made to the following description taken in connection with the accompanying drawings.

Fig. 1 is a schematic diagram of connectionsv of a simplifled computing system showing most of the circuits in block form.

Fig. 2 is an exploded isometric a target.

viewof a portion of Fig. 3 is a cross-sectional view of a portion of the target shown in Fig. 1.

Fig. 4 is a schematic diagram of connections similar to Fig. l but employing a double target combination and providing control circuits for energizing four motors to show the flight of a missile on a screen giving the illusion of three dimensions.

Fig. 5 is a cross-sectional view of a simplified form of target.

Fig. 6 is a cross-sectional view showing a golf ball on a tee with arrangements for breaking a circuit when the ball is struck.

Fig. 7 is a cross-sectional view similar to Fig. 6 but showing means for making a circuit when the ball is struck.

Fig. 8 is a schematic diagram showing a double projector system for projecting two beams of light on a large viewing screen to show the flight of a missile in three dimensions.

Fig. 9 is a plan view, with some parts in section, of an alternate system of sensing the start of the missile by employing a photoelectric cell and a focused light beam.

Fig. 10 is a schematic diagram of connections for determining the length of flight by recordin the elapsed time on a decade sealer.

Fig. 11 shows an alternate arrangement, similar to Fig. 10 but using a time clock as an indicating device.

Fig. 12 is a graph to explain the action of one of the circuits of Fig. 13 as applied to the actual flight of a small missile.

Figs. 13 and 14 when placed side by side form a complete and detailed wiring diagram of the computing system including the motors which control the display device.

Referring now to Fig. 1 a ball 10 is positioned on a tee 11 which is supported by a base 12. Directly underneath the tee is an electrical contact 13 which closes a circuit when the ball 10 is struck. Details of the tee and alternative arrangements of contacts are shown in Figs. 6 and 7. In series with contacts 13 is a start circuit 14, the output of which is connected to a velocity computing circuit 15. This circuit also produces an electrical pulse which can be applied to a distance-measuring indicator 16.

The ball 16 is impelled in a general direction indicated by arrow 17 and strikes a target combination 18. Details of this target are shown in Figs. 2 and 3.

wires 21. Between each of the wires a strip of foam or sponge rubber 22 is mounted. These strips are thicker than the diameter of the wires 21 and keep them insulated from other conductors before and after being struck by the ball. On the top surface of strips 22 a second series of diagonal conductors 23 is mounted. On top of foam rubber is cemented having a plurality of channels 25 in which are cemented a third array of conductors 26.

When not in an actuated condition the three arrays of conductors 21, 23, and 26 are insulated from each other but when the ball it is driven against the target mat, contact is made between the three sets of conductors at the point where the ball strikes. In order to sense the position of impact external circuits are employed. The diagonal conductors 23 are joined together at their exbeing connected to ground and the upper end connected to a loft circuit 34. In I e manner the vertical conduc- 3 tors 21 are connected to a series of resistors 28 with the two ends of this array connected to the direction circuit 33 and the center point connected to ground.

It will be obvious that when a ball is struck to any location on the target mat and contact is made between the three sets of conductors a positive potential is applied to conductor 30 and to either 29 or 31, which is peculiar to the location of the impact. The voltage received on conductor 39 is applied to a stop circuit 32 which delivers a signal to the velocity circuit 15. The difference in timing between the signals received from start circuit 14 and stop circuit 32 is a measure of the speed of the ball and calculation of this speed is made by circuit for the determination of distance.

The voltage transmitted over conductor 31 or conductor 29 is applied to direction circuit 33 for the determination of the horizontal component of direction and in a similar manner the potential value transmitted over conductor is applied to loft circuit 34 for determination of the vertical component of direction. The .output of circuit 33 is applied to a direction indicating meter 35 and is also applied to a control circuit 36 which .governs a motor 37 to shift the base of an optical system 38 to indicate the direction of the ball on a screen 40.

The output of circuit 34 is applied to a control circuit :41 which controls the power sent to a motor 42. This motor is coupled by shaft 43 to a nut 44 which raises and lowers the base 38 of the projection system, thereby indicating on screen the vertical positions that the ball 10 would have taken in actual fiight. control circuit 41 also controls another motor 45 which opens and closes an iris diaphragm 46. The opening of this diaphragm is focused by a lens 47 so that an image of the diaphragm appears on the screen surface, therefore the opening of the diaphragm controls the diameter of the image on the screen. When the ball is struck, motor 4-5 is controlled to close iris 46 to make the image of the ball on the screen smaller and smaller, thereby simulating the efiect of distance. The projection system also includes the usual lamp 48 and condensing lens 50.

The above description relates to a system which contains only one target combination and makes no allowance for the spin of the ball which results in a hook or a slice. A more complete system which senses the spin given to the ball and which computes the efi'ect of this spin and its eilect on the trajectory is shown in Fig. 4 taken in combination with the projection system shown in Fig. 8.

The sensing system shown in Fig. 4 is similar in many respects to that shown in Fig. 1. The ball support and the start-stop circuits are the same as are also the velocitymeasuring circuits and the distance indicator 16. How ever, this system has an additional target 53. which is employed to determine the impact position of the ball in its horizontal position only after it has been reflected or bounced from target 18. The construction of this target is shown in detail in Fig. 5 and comprises a supporting panel 52 of conductive material. Cemented to this panel is a slab of foam or sponge rubber 53 having spaced channels 54 and a series of conductors 55 eemented in the channels. As indicated in the drawing the conductors are close to but not in contact with the base plate 52; however, when the ball hits the rubber slab 53 one or two of the conductors 55 will be pressed into contact with plate 52. The extremities of conductors 55 are joined by an array of resistors 56 forming a voltage divider, the two ends of which are connected to a spin circuit 58 with the center wire connected to ground. If the ball is hit toward the first target combination 1% without any spin it will first cause contact between one of the conductors 21 and the conductors 23 (not shown -in Fig. 4). Then it will bounce upwardly to target 51 and cause contact between one of the .wires 55' and the base plate 52 (Fig. 5). With no spin, contacting wires 21 and 55 will ,be in the same vertical plane and the The motor potential produced on conductor 31 or 29 will be substantially the same as the potential produced on conductor 57 or 59. Since these potentials are equal, the diiferential circuit 63 will record a zero spin and the control circuits which follow will be governed accordingly. If the ball has a spin the first bounce from target 18 will be to the right or left and contact will be made with a wire which is not in the same vertical plane as the contact wire 21 in the lower target. Difierent voltages will then be produced on conductors 31, 29 and 57, 59 and the differential circuit 63 will sense this difference and apply it to the control circuit 62.

The vertical component of direction is sensed by one of the wires 26 and the resistor array 27. A corresponding voltage value is sent over conductor 30 to circuit 34. The output of this circuit is applied to the vertical motor control 41 but it will be obvious that the actual height to which the ball travels is a function of both the vertical direction and the velocity, therefore the motion of motor 42 (see Fig. 8) is combined with the motion of motor 71 as will be described in detail later. Motor 42 contains two windings, one which causes the motor to elevate the image of the ball on the screen, and a second which causes the motor to reverse and lower the image. The first winding is connected to the velocity circuit 15 while the second is connected to the loft or vertical direction circuit 34. These circuits will be described in detail later when Figs. 13 and 14 are described.

The amount of spin sensed by the two target mats and by circuits 33, 58, and 63 is applied through control circuit 62 to motor 66 (Fig. 8) which revolves an amount which is proportional to the spin given to the ball. This motion is combined with the motion of motor 63 by gear differential 73 and applied to a screw and nut arrangement 7 8 to turn base 38 and direct the image of the ball on the screen in a horizontal direction.

Referring now specifically to Fig. 8 a double projection system isshown which projects two spots on a screen 40. One of the spots is produced by a first projector 65 which is similar in all respects to the projector shown in Fig. l and has an iris 46, a projection lens 47, a lamp 48, and a condensing system 50. The first projection system 65 can be moved about a vertical axis 69 by a motor 67. The iris is controlled by motor 45. The second projection system is secured to a base 38 which also holds the first projection system 65. Base 33 can be rotated about a vertical axis which passes through gear 44 by either one of motors 68 and 66. These motors move both projection systems including the other motors. The large base 38 can be rotated about a horizontal axis by a motor 42 which acts on a nut 44. Each projection system includes a variable iris 46, both being controlled by motors 45.

A sheet of polarizing material, such as Poiaroid, is included in the assembly of each of the projection lenses 47, one such sheet being set at an angle of 45 degrees from the vertical while the ohter polarizing sheet is set at an angle degrees from the first. This arrangement produces two light beams polarized at right angles to each other.

The images on screen 4%) are to be viewed through polarizing glasses arranged so that one eye will receive light polarized only in one direction while the other eye will receive light polarized at an angle 90 degrees from the first. This system of producing pictures of apparently three dimensions is well known and its theory of operation need not be described here in detail. When the two spots on the screen are the same distance apart as the distance between the eyes they produce a single image to the viewer which appears to be an infinite distance away. When the spots are brought closer together the image appears to approach the observer and when the spots coincide the image appears to be on the surface of the screen. Moving the spot produced by the left hand projection system to the right of the spot produced by v the right hand system produces the efiect of moving the image still closer to the observer. It will be obvious from the description given of this figure-and Fig. 1 that motors 68* and 66' which move both projection systems, control thehorizontal direction of thetrajectory, while motor 67 which is mounted on themain base 38 and which turns only one of the projection systemscontrols-the illusion of distance.

In order to explain the-details of the circuits shown inblock in Figs. 1 ancl'4, a complete schematic diagram of connections is shown in-Figs; l3 and-l4. This circuit contains three contact arrays-18a, 18b, and 51 which are equivalent to the two arrays 18 and 51. Target array 18a is connected to a voltage divider 27 and to a capacitor 90 which is charged to a voltage when the ball strikes the target. The voltage received by the capacitor is proportional to the vertical direction of the ball and this value is applied to a pentode vacuum tube 91 over conductor 30 to place the tube in conducting condition. The charge on capacitor 90 leaks 011 through a resistor 92 until the tube again reverts to its normal non-conducting I condition. An additional resistor 27A is necessary it the contact wires in mat 18A are held in contact for a small time interval.

The anode of pentode 91 is connected by means of conductors 76 and 77, in series with a field winding 93 of an alternatingcurrent motor 42 and the other end of the field winding is connected to a positive source of potential. Motor 42 of Fig. 14 corresponds to motor 42 shown in Fig. 8 which turns nut 44 to elevate the image of the ball onscreen 40. The anode conductor 76 from tube 91 is also connected to a field winding 99 by conductor 8? which is part of motor 45 (Figs. 8 and 14) to decrease the size of the ball image on the screen. The control electrode of tube 91 is connected to a source 94 of cycle alternating current which is applied continuously but has no effect when capacitor is uncharged since the negative bias on the second control electrode prevents anode-cathode conduction.

in Fig. 8 the Z terminal is shown connected to two motors 45'which control two irises 46, a motor 67 which controls the illusion of distance, and motor 71 which is coupled to a'gear differential 72 which will be described hereinafter. It will be obvious that a single motor with multiple'mechanica'l connections could produce-the same result and the'invention is not limited to the number of motors run by any one of the motor control circuits. T he'circ'uits 14, 15, 32, and 64 which provide the control power for all motors connected to the Z terminal are all described in detail in connection with Figs. 13 andl i.

The start circuit 14 includes relay A and relay B (Fig. 13

The stop circuit 32 includes vacuum tube 91, relay C, and their associated circuits. The velocity circuit 15 includes tubes 114, 112, 127, and their associated circuit components. The motor control circuit 64 includes a'6ll cycle source ofpower (Fig. 13) and a reset circuit 1"'9167 (Fig. 14).

The screen 415 may be a white projection screen but it has been found that the illusion of playing in' the open isrnore pronounced if a picture'of a golf course is painted on the screenwith the cup. and cup pennant at the middle of the screen. In such a picture the area between the cup and the bottom of the picture represents the extent of thefairway between the teeand the putting green and a ball driven to a position half-wayv between the tee and the cup should be shown on the screen as about half-way between the center of the screen and the lower border. To place the final position of the image in its proper location a gear differential '7'2 is provided with couplings to motors 42 and-71. The voltages and mechanical arrangem nts are such that motor 42, if acting alone, moves the ball image from a Starting position just below the screen border to its calculatedheight and then down to the same position. Motor 71, due to its coupling through gear differential 72 causes the final position of the image to be somewherein the picture'foreg'round, the greater the velocity, the closcr-thefinal position of the projected image to the cup.

Contact array 18B contains a plurality of vertical condoctors, the ends of which are connected to a voltage divider 28, grounded in the middle through resistor 96. The ends ofthe voltage divider are each connected, in series with a rectifier unit, to capacitors A and 95B and also to control grids in pentodes 89 and 97. In addition, the ends of voltage divider 28 are connected to two other rectifiers 81 and 82 which in turn are connected to capacitors 162 and 160 in the spin circuit connected to target mat 51. The anodes of tubes 89 and 97 are connected by conductors 83 and 84 to windings 161 and 98 (Fig. 14) in motor 63 and then to a source of positive potential.

Contact array 51 is similar to array 18B and contains a plurality of vertical contact wires which are connected to a voltage divider 56, grounded in the middle in series with a resistor 35. The ends of the voltage divider are connected to capacitors 113i and 162 each in series with a rectifier component, and also connected to control grids in pentodes 102 and 113. The anodes of pentodes 192 and 113 are connected by connectors 86 and 87 to windings 49 and 193 in motor 66 which controls the horizontal direction of the projected image due to spin. The other ends of these windings are connected to a source of positive potential.

All four motors, including the Z motor 45, have a second field Winding (10 i, 105, 1%, and 109 being shown in Fig. 14). These windings are normally connected to the alternating current source in a manner which turns the motors in a direction which indicates the flight of the ball after it has een struck. After this initial operation the motors must be reset to the zero or start position and to do this reversing contacts 107, 108 110, and 119 operated by relays E, G, I, and K are connected in the field supply to reverse the phase of the current and run the motors in a reverse direction.

Motor 42 which controls the elevation and fall of the projection system contains an additional field winding 111 Wound in a reverse direction compared to winding 93 and is used for the purpose of returning the projection system to level alignment; that is, to lower the image of the ball to ground level at the end of its trajectory. This reverse winding is in series with the positive source of direct current and an anode of a vacuum tube 112. This tube, which is normally non-conducting, has its number one control electrode connected to the source of alternating current 94 and its number two control electrode connected to the output of an amplifier tube 114 which receives its input from a voltage divider 115 which is connected between a negative source of direct current potential and a relay contact 124 which is made at thestart of the flight.

The missile or ball 10 is indiciated in Fig. 13 above a contact device 13which is operated when the ball is struck. Contacts 13 complete a circuit from a positive source of direct current 116 through the winding of a start relay A, then through contacts 117 of a stop relay C to ground. When the start relay A operates it makes three contacts 118, 120, and 121. Contacts 118 are locking contacts and hold relay A in operated condition until the locking circuit is broken. Contacts 129 supply an actuating voltage to a second start relay B, locking it into operating condition through locking contacts 122 and at the same time breaking contacts 123 and making contacts 124. This action transfers a capacitor 125 from a charging circuit containing a source of potential 126 to a discharge circuit which includes the voltage divider 115.

Also associated with voltage divider 115 is a gas-filled tetrode 127 which starts conducting as soon as relay B is operated due to the positive voltage applied to itscontrol electrode. The anode of this tetrode is connected through an indicator relay D to the source of alternating current 94 and provides pulsating current to keep relay D 'may have several pairs of contacts 7 as long as the control electrode fire the tetrode 127. Relay D depending upon the number and type of indicating devices used. Figs. 10 and 11 show two of such indicating arrangements.

Relay contacts 121 connect a source of high frequency alternating current (10 kilocycles) through a time constant circuit 139, 131 to the control electrode of a pentode 132. The anode of this pentode is connected to the positive side of capacitor 125 and aids in discharging it. A rectifier 133 converts the high frequency supply to a pulsating voltage which biases the control electrode to cause the tube to dischar e capacitor 125 at a slow rate.

When the ball strikes the first target, tube 91 is rendered conducting and a pulsating voltage is present on the in an operating condition is sufficiently positive to anode conductor. Some of this will be passed through a capacitor 134 and rectifier 135 to energize the winding of relay C and open contacts 117. These contacts are in series with the winding of relay A hence as soon as relay C is operated relay A is normalized.

In order to reset the motors and the projection system to the normal or start condition a reset switch is employed. This switch is operated manually and comprises six contact pairs which are shown in Figs. 13 and 14. Reset contacts 136 break the locking circuit which normally holds relay B in its operated condition. Reset contacts 138 control the operation of relay F when contacts 139 are closed. Relay F includes locking contacts 140, contacts 141 which discharge capacitor 90, and contacts 142 which operate the reversing relay E when contacts 143 are closed.

Reset contacts 144 associated with the X motor 68 operate in the same manner controlling the contacts of relay H when cam operated contacts 145 are closed. And

in a similar manner contacts 146 on the H relay cause the reversing relay G to operate if contacts 147 are closed. It should be noted that when the motor returns to its zero position contacts 145 and 147 are opened and relays H and G are both normalized. Also, if the motor had not moved at all, as may be the case with the X motor 66 which is governed by spin, the operation of the reset contacts produces no action.

Reset contacts 148 and 164 associated with motors X 'and Z and relays I, I, K and L are exactly similar to those already described.

The operation of the circuit is as follows: With the 'four motors in their normal or zero position, let it be assumed that the ball is struck toward the right of the center line of the targets and travels to contact arrays 18A, 18B, and 51 making contact at each and applying a voltage value to conductors 3t), 29, and 57. Driving the ball away from the T makes contacts 13 and operates start relays A and B as previously described. When the B relay operates, charged capacitor 125 is connected to voltage divider 115 and the capacitor discharges slowly through this circuit. An additional discharge path is also made available through the anode-cathode circuit of pentode 132 by the application of a bias potential to the control electrode through contacts 121. Capacitor 125 discharges through the tube at a much greater rate than through the voltage divider.

' When the ball hits contact array 18A, capacitor 99 is charged and pentode 91 is energized causing relay C to be operated, opening contacts 117, normalizing relay A and opening contacts 121. As soon as these contacts are open the anode-cathode circuit through pentode 132 is rendered non-conductive and the capacitor discharges only through the voltage divider at a much lower rate. When capacitor 1.25 has finally discharged to a voltage which is less than the firing voltage of the gas-filled tetrode 127 the anode-cathode current is cut off and relay D is'normalized.

It should be noted that relay D is in an operated condition from the time the ball is struck until the time of the total discharge of capacitor 125. During this time interval the capacitor is discharged at a comparatively fast rate for some of the time and at a slow rate for the remainder of the time. The duration of this time interval is roughly proportional to the time of flight, and contacts operated by relay D can be used to control indicators calibrated in yards to show the length of the trajectory.

When the ball strikes contact arrays 18A, capacitor is charged to the voltage value corresponding to the height of the impact. This charge leaks 011 through resister @2 but during the greater part of the discharge pentode 91 is held conductive sending an operating current through its anode conductor to field winding 93 causing the Y motor 42 to turn and elevate the image of the ball on the screen. The value of capacitor 90 and. resistor 92 are chosen so as to stop motor 42 about the time the hall would have traveled two-thirds of its free flight distance. At this point winding 111 receives current from the anode in tetrode 112 and reverses the direction of the Y motor to indicate the fall of the ball to the terrain level. Fig. 12 shows the approximate trajectory of the ball with two-thirds of the time of flight consumed in the rise andone-third of the period for the fall. Tetrode 112 derives its actuating voltage from the output of triode 114 coupled to voltage divider 115. Triode 11 i is normallynon-conducting but as soon as contacts 124- are made it is rendered conducting and in this condition its anode is at a reduced potential, lowering the potential of the second control electrode of tetrode 112 below the cut-011 value and rendering the anodecathode circuit non-conducting. During the discharge of capacitor 125 the potential of the control electrode of triode 114 is reduced until the tetrode 112 starts conducting and reverses motor 42.

When the ball bounces from the first target combination 18 (including 18A and 18B) it then hits target 51. The circuits connected to contact arrays 18B and 51 operate as follows: If a ball strikes the right side of contact array 18B it makes a contact between one of the diagonal wires (shown horizontal in Fig. 13) and a vertical wire, thereby applying a voltage to divider 28 and charging capacitor 958 to a potential which is proportional to the horizontal direction of the ball. This same potential is applied to one of the control grids in pentode 97 and the tube conducts, sending a current (modulated by the 60 cycle source 94) over conductor 84 to winding 98 of motor 68 causing it to rotate and control the projection system to move the image of the ball to the right on the screen. At the same time, due to the connection through rectifier 82, capacitor 162 and the control grid in pentode 113 are provided with a similar charge and a modulated current is sent over anode conductor 86 to winding 49 tending to turn motor 66 in a direction which would move the image to the left. However, if the hall has no spin and bounces from array 1813 to array 51 hitting similar right-hand vertical wires a similar voltage is applied to voltage divider 56 and capacitor is charged to the same potential as capacitor 9513, thereby sending a modulated current over anode conductor 87 to winding 163 of motor 66. This Winding tends to turn the motor to move the image to the right and counteracts the current in winding 49. The net result is that motor 66 does not move at all. If spin, to the right or left, is

V imparted to the ball when it is hit, the ball moves to the capacitors 162 and 100 to different potentials and causing motor 66 to move to the right or left, altering the image motion through gear differential 72 to show the efiects of spin. In actual flight on a golf course the effects of spin (hook or slice) are not evident until after the ball has progressed about half of its total trajectory distance. The same efifect is shown on the screen by adding a heavy wheel to the shaft of motor 66 so that it starts its rotation with a slight time delay. The current from erra a-001 tube 113 or 102m motor'winding 49 or 103 starts as soon aseither capacitor 162 or 100' is charged, and a small amount of power is lost because of the slow starting characteristics of motor 66. However, during the slow start, energy is stored in the wheel and the motor runs faster near theend of the motor travel than if the wheel had not been attached. This eifect also adds realism to the display.

After the motors have turned the controls which move the projected spot through its calculated trajectory the main operation is concluded and the machine must be reset to accommodate another flight. The ball is first placed on the tee 11 which breaks contacts 13. Then the reset switch R is manually operated, breaking contacts 136'and 137 and making contacts 133, 144, 148, and 164. This switching action normalizes the start and stop circuits and energizes the reset circuits of all four motors to return them to the start position. Motor 42 always turns first clockwise (closing contacts 143) and then counterclockwise to show the rise and fall of the missile. When the reset contacts 138 are closed relays E and F are both operated, reversing the current in winding 164 and sending a modulated current through winding 93. This action turns the Y motor 42 in a counterclockwise direction to restore it to its initial position. Current for motor windings 103, 98, 93, and 99 is provided by relay contacts 141, 166, 165, and 167 which connect one of the control electrodes in tubes 91, 113, and 97 to ground thereby making these tubes conductive. The additional action of the reset relays F, H, L and J has already been described. Reversing relays E, I, G, and K are operated only when the reset keys 138, 144, 148, and 164 are depressed and then only when the motors have been moved in a clockwise direction to close the contactsoperated by the end cams on the motor shafts. The reversing relays operate double-pole, double-throw switches to change the phase of the alternating current in motor windings 104, 105, 106, and 109.

The above description of Figs. 13 and 14 applies to the block diagram shown in Fig. 4 where four motors are energized to produce a display Which shows direction and the result of spin. The block diagram of Fig. 1 comprises only two contact arrays (constructed in a single unit) and controls three motors 42, 45, and 37 to show a display which is controlled by velocity and direction (both horizontal and vertical). A detailed diagram of connections of the arrangement of Fig. 1 may be obtained from Figs. 13 and 14 by omitting the components and wiring enclosed in dotted lines 158. This area includes the third array 51 together with its associated circuits and the spin motor 66 with its reset relays.

Fig. 9 shows a schematic view of an alternate type of start contact device. The ball 10 is interposed in the path of a light beam from a shielded lamp 150 focused by a lens 151 and directed toward a photoelectric cell 152 encased in a light shield 153. When the ball is struck it moves out of the way of the light beam which actuates the photo cell and transmits the same circuit voltages as was done by contacts 13.

Fig. 10 indicates one of the possible uses of the contacts associated with relay D in Fig. 13. When contacts 154 are made potential is applied to a decade counting device 155 which starts to count at a rate which can be calibrated to read in yards of trajectory distance. At the end of the time of flight contacts 154 open and the counting circuit 155 is de-energized stopping the counting action but indicating the distance by signal lamps.

Fig. 11 is another time-of-fiight indicator and operates on a similar principle. Indicator 156 is an interval time recorder run by an external source of alternating current power. The motor pointer starts when contacts 154 are made and stops when they are broken. This indicator may also be calibrated in yards.

Fig; 4 shows the-first target combination 18 inclined at an angle which directs a bouncing-nussile'upwardly to a second target 51. An alternate arrangement comprises the obvious disposition'of afirst target combination at a 45 degree angle but-directing a bouncing missile downwardly toward the second target which is set below the first. The second target may beset to direct the bouncing missile either toward or away from the initial start position.

Figs. 1 to 5, show contact arrays having a planefiat formation. It is understandable that greater accuracy will be attained if the arrays are given aslight curvature, especially if they are positioned close to the start positionand extend forconsiderable area. The most accurate arrays have a conical formation with the axis of the cone passing vertically through the start position.

From the above descriptionit will be evident that the invention provides an accurate and convenient means for viewing the path of a struck missile on a screen as seen from a position adjacent to the tee;

While there have been described and illustrated specific embodiments of the invention, it will be obvious that various changes and modificationscan be made therein without departing'from the field of the invention which should be limited only by the scope of the ap pended claims;

I claim:

1. A game practice apparatus comprising; means for generating a primary signal responsive to the displacement of a missile from a'starting position; a target combination disposed in the path of the missile andincluding two arrays of contact means adapted to be actuated by the missile for locating the missiles' horizontal and vertical impact positions thereupon; another target including an array of contact means disposed for receiving sai'dmissile after impact on said target combination to determine'the missiles second'horizontal impact position for subsequent determination of spin; a computing system connected to the primary signal generating means for receiving the signal therefrom and also connected to said three arrays of contact means for receiving signals therefrom; said computing system including means which produces a first output signal responsive to the missiles time of flight from the start position to one of said arrays, second and third output signals responsive respectively to the horizontal and vertical impact positions on the two arrays, and a fourth output signal proportional to the missiles spin and responsive to the difference between the missiles successive horizontal impact positions on said arrays; and a movable display device operated by electromagnetic means controlled by said first output signal to move the display device to give the illusion of distance, by said second and third output signals to move the display device to indicate the missiles non-intercepted combined horizontal and vertical movements in free space, and by said fourth output signal to move the display device horizontally to indicate the results of the missiles spin.

2. A game practice apparatus comprising; means for generating a primary signal responsive to the displacement of a missile from a starting position; a target combination disposed in the path of the missile and including two arrays of contact means adapted to be actuated by the impact of the missile for locating the missiles horizontal and vertical impact positions thereupon; another target including an array of contact means disposed for receiving said missile after impact on said target combination to determine the missiles second horizontal impact position for subsequent determination of spin; said target combination and target angularly positioned with respect to each other; a computing system connected to the primary signal generating means for receiving the signal therefrom and also connected to said three arrays of contact means for receiving signals therefrom; said computing system including means which produces a first output signal responsive to the missiles time of flight from the start position to one of said arrays, second and third output signals responsive respectively to the horizontal and vertical impact positions on the two arrays, and a fourth output signal proportional to the missiles spin and responsive to the diiference between the missiles successive horizontal impact positions on said arrays; and a movable display device operated by electromagnetic means controlled by said first output signal to move the display device to give the illusion of distance, by said second and third output signals to move the display device to indicate the missiles non-intercepted combined horizontal and vertical movements infree space, and by said fourth output signal to move the display device horizontally to indicate the results of the missiles spin.

3. A game practice apparatus comprising; means for generating a primary signal responsive to the displacement of a missile from a starting position; a target combination disposed in the path of the missile and including two arrays of contact means adapted to be actuated by the missile for locating the missiles horizontal and vertical impact positions thereupon; another target'including an array of contact means disposed for receiving said missile after impact on said target combination to determine the missiles second horizontal impact position for subsequent determination of spin; a computing system connected to the primary signal generating means for receiving the signal therefrom and also connected to said three arrays of contact means for receiving signals therefrom; said computing system including means which produces a first output signal responsive to the missiles time of flight from the start position'to one of said arrays, second and third output signals responsive respectively to the horizontal and vertical impact positions on the two arrays, and a fourth output signal proportional to the missiles spin and responsive to the difference between the missiles successive horizontal impact positions on said arrays; and a movable optical projector operated by electromagnetic means controlled by said first output signal to reduce the size of a projected spot on a viewing screen, by the second and third output signals to move the projected spot to indicate the missiles non-intercepted combined horizontal and verticalmovements in free space, and by said fourth output signal to move the projected spot horizontally to indicate the results of the missiles spin.

4. A game practice apparatus in accordance with claim 3 wherein said electromagnetic means comprises a plurality of electric motors.

5. A game practice apparatus as set forth in claim 3 wherein said movable optical projector includes means for projecting two spots on a viewing screen, filtering means for projecting polarized light for each spot at an angle of ninety degrees from each other, and motor control means controlled by said first output signal for moving one of the spots on the screen to create a display which gives an illusion of three dimensions when viewed through crossed polarizing filtering means.

6. A game practice apparatus as set forth in claim 5 wherein the electromagnetic means controlled by said second and fourth output signals are motors and said movable optical projector is coupled to a mechanical gear differential which combines the movements of the motors controlled by the second and fourth output signals.

References Eited in the file of this patent UNITED STATES PATENTS 2,102,166 Roberts Dec. 14, 1937 2,331,236 Schaefer Oct. 5, 1943 r 2,331,237 Schaefer Oct. 5, 1943 2,581,738 Williams Jan. 8, 1952 

